/* $NetBSD: secmodel.c,v 1.2 2014/11/04 16:01:58 maxv Exp $ */
/*-
* Copyright (c) 2011 Elad Efrat <
[email protected]>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/types.h>
#include <sys/param.h>
#include <sys/errno.h>
#include <sys/atomic.h>
#include <sys/kauth.h>
#include <sys/kmem.h>
#include <sys/queue.h>
#include <sys/rwlock.h>
#include <secmodel/secmodel.h>
#include <prop/proplib.h>
/* List of secmodels, parameters, and lock. */
static LIST_HEAD(, secmodel_descr) secmodels =
LIST_HEAD_INITIALIZER(secmodels);
static unsigned int secmodel_copy_cred_on_fork = false;
static krwlock_t secmodels_lock;
static int nsecmodels = 0; /* number of registered secmodels */
static int secmodel_plug(secmodel_t);
static int secmodel_unplug(secmodel_t);
int
secmodel_nsecmodels(void)
{
return nsecmodels;
}
void
secmodel_init(void)
{
rw_init(&secmodels_lock);
secmodel_copy_cred_on_fork = false;
}
/*
* Register a new secmodel.
*/
int
secmodel_register(secmodel_t *secmodel, const char *id, const char *name,
prop_dictionary_t behavior,
secmodel_eval_t eval, secmodel_setinfo_t setinfo)
{
int err;
secmodel_t sm;
sm = kmem_alloc(sizeof(*sm), KM_SLEEP);
sm->sm_id = id;
sm->sm_name = name;
sm->sm_behavior = behavior;
sm->sm_eval = eval;
sm->sm_setinfo = setinfo;
err = secmodel_plug(sm);
if (err == 0) {
atomic_inc_uint(&nsecmodels);
} else {
kmem_free(sm, sizeof(*sm));
sm = NULL;
}
*secmodel = sm;
return err;
}
/*
* Deregister a secmodel.
*/
int
secmodel_deregister(secmodel_t sm)
{
int error;
error = secmodel_unplug(sm);
if (error == 0) {
atomic_dec_uint(&nsecmodels);
kmem_free(sm, sizeof(*sm));
}
return error;
}
/*
* Lookup a secmodel by its id.
*
* Requires "secmodels_lock" handling by the caller.
*/
static secmodel_t
secmodel_lookup(const char *id)
{
secmodel_t tsm;
KASSERT(rw_lock_held(&secmodels_lock));
LIST_FOREACH(tsm, &secmodels, sm_list) {
if (strcasecmp(tsm->sm_id, id) == 0) {
return tsm;
}
}
return NULL;
}
/*
* Adjust system-global secmodel behavior following the addition
* or removal of a secmodel.
*
* Requires "secmodels_lock" to be held by the caller.
*/
static void
secmodel_adjust_behavior(secmodel_t sm, bool added)
{
bool r, b;
KASSERT(rw_write_held(&secmodels_lock));
#define ADJUST_COUNTER(which, added) \
do { \
if (added) { \
(which)++; \
} else { \
if ((which) > 0) \
(which)--; \
} \
} while (/*CONSTCOND*/0)
/* Copy credentials on fork? */
r = prop_dictionary_get_bool(sm->sm_behavior, "copy-cred-on-fork", &b);
if (r) {
ADJUST_COUNTER(secmodel_copy_cred_on_fork, added);
}
#undef ADJUST_COUNTER
}
static int
secmodel_plug(secmodel_t sm)
{
secmodel_t tsm;
int error = 0;
if (sm == NULL)
return EFAULT;
/* Check if the secmodel is already present. */
rw_enter(&secmodels_lock, RW_WRITER);
tsm = secmodel_lookup(sm->sm_id);
if (tsm != NULL) {
error = EEXIST;
goto out;
}
/* Add the secmodel. */
LIST_INSERT_HEAD(&secmodels, sm, sm_list);
/* Adjust behavior. */
secmodel_adjust_behavior(sm, true);
out:
/* Unlock the secmodels list. */
rw_exit(&secmodels_lock);
return error;
}
static int
secmodel_unplug(secmodel_t sm)
{
secmodel_t tsm;
int error = 0;
if (sm == NULL)
return EFAULT;
/* Make sure the secmodel is present. */
rw_enter(&secmodels_lock, RW_WRITER);
tsm = secmodel_lookup(sm->sm_id);
if (tsm == NULL) {
error = ENOENT;
goto out;
}
/* Remove the secmodel. */
LIST_REMOVE(tsm, sm_list);
/* Adjust behavior. */
secmodel_adjust_behavior(tsm, false);
out:
/* Unlock the secmodels list. */
rw_exit(&secmodels_lock);
return error;
}
/* XXX TODO */
int
secmodel_setinfo(const char *id, void *v, int *err)
{
return EOPNOTSUPP;
}
int
secmodel_eval(const char *id, const char *what, void *arg, void *ret)
{
secmodel_t sm;
int error = 0;
rw_enter(&secmodels_lock, RW_READER);
sm = secmodel_lookup(id);
if (sm == NULL) {
error = EINVAL;
goto out;
}
if (sm->sm_eval == NULL) {
error = ENOENT;
goto out;
}
if (ret == NULL) {
error = EFAULT;
goto out;
}
error = sm->sm_eval(what, arg, ret);
/* pass error from a secmodel(9) callback as a negative value */
error = -error;
out:
rw_exit(&secmodels_lock);
return error;
}
